[llvm] 5e7a42c - [llvm-objdump] Replace array_pod_sort with llvm::stable_sort

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2020-03-25T08:13:40-07:00
New Revision: 5e7a42cf077d2555038be1218907174f4df8e5a5

URL: https://github.com/llvm/llvm-project/commit/5e7a42cf077d2555038be1218907174f4df8e5a5
DIFF: https://github.com/llvm/llvm-project/commit/5e7a42cf077d2555038be1218907174f4df8e5a5.diff

LOG: [llvm-objdump] Replace array_pod_sort with llvm::stable_sort

llvm-objdump.cpp has 3 array_pod_sort() calls used for symbolization.
array_pod_start() calls qsort() internally and can have different
behaviors across different libcs. Use llvm::stable_sort instead.

Reviewed By: davidb, thopre

Differential Revision: https://reviews.llvm.org/D76739

Added: 
    

Modified: 
    llvm/tools/llvm-objdump/llvm-objdump.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 1cfd06d2cef5..768ddfedd478 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -1202,11 +1202,13 @@ static void disassembleObject(const Target *TheTarget, const ObjectFile *Obj,
   StringSaver Saver(A);
   addPltEntries(Obj, AllSymbols, Saver);
 
-  // Create a mapping from virtual address to section.
+  // Create a mapping from virtual address to section. An empty section can
+  // cause more than one section at the same address. Use a stable sort to
+  // stabalize the output.
   std::vector<std::pair<uint64_t, SectionRef>> SectionAddresses;
   for (SectionRef Sec : Obj->sections())
     SectionAddresses.emplace_back(Sec.getAddress(), Sec);
-  array_pod_sort(SectionAddresses.begin(), SectionAddresses.end());
+  stable_sort(SectionAddresses);
 
   // Linked executables (.exe and .dll files) typically don't include a real
   // symbol table but they might contain an export table.
@@ -1236,11 +1238,12 @@ static void disassembleObject(const Target *TheTarget, const ObjectFile *Obj,
   }
 
   // Sort all the symbols, this allows us to use a simple binary search to find
-  // a symbol near an address.
+  // Multiple symbols can have the same address. Use a stable sort to stabalize
+  // the output.
   StringSet<> FoundDisasmSymbolSet;
   for (std::pair<const SectionRef, SectionSymbolsTy> &SecSyms : AllSymbols)
-    array_pod_sort(SecSyms.second.begin(), SecSyms.second.end());
-  array_pod_sort(AbsoluteSymbols.begin(), AbsoluteSymbols.end());
+    stable_sort(SecSyms.second);
+  stable_sort(AbsoluteSymbols);
 
   for (const SectionRef &Section : ToolSectionFilter(*Obj)) {
     if (FilterSections.empty() && !DisassembleAll &&